1. Field of the Invention
The invention relates to a sulfur dioxide detector device using SO.sub.2 -oxidant bioagent in order to detect concentration of sulfurous acid contained in processed foods or the like.
2. Description of Prior
In order to detect concentration of sulfite used as an anti-oxidant in processed foods or the like, specified bioagent such as microbe and enzyme has been employed to oxidize sulfurous acid to sulfuric acid. An consumed amount of the dissolved oxygen is equivalent to the concentration of the sulfite in the anti-oxidant.
To embody the detection, a SO.sub.2 -detector device is introduced in which a bio-membrane is provided which has the bioagent between a gas permeable membrane and an immobilized membrane. Then, SO.sub.2 -involved solution is adapted circulate through an inlet, cell and outlet. When the SO.sub.2 -involved solution enters the cell, the solution flows along the gas permeable membrane to allow SO.sub.2 to pass through the bio-membrane. During the passage of the SO.sub.2, the SO.sub.2 is oxidized to sulfuric acid by dissolved oxygen, an amount of which corresponds to an output difference occasioned from an oxygen concentration sensor.
In this SO.sub.2 -detector device, however, a fluctuation of liquid pressure and foam in the cell causes to deviate from an accurate concentration detection particularly when replenishing the SO.sub.2 -involved solution.
Further, the bio-membrane is attached to a spherical oxygen electrode of the oxygen concentration sensor, deliberate care and experienced skill are unavoidably needed when replacing the bio-membrane. It is also necessary to remove the bio-membrane whenever replacing a battery cell of the oxygen concentration sensor. This makes handling of the SO.sub.2 -detector device troublesome and complicated.
Therefore, it is an object of the invention to provide a sulfur dioxide detector device which is capable of quickly detecting sulfurous acid concentration with high accuracy.
It is another object of the invention to provide a sulfur dioxide detector device which is capable of replacing a battery cell and a bio-membrane individually, thus making handling of the device relatively easy.